Fairfax County will soon begin to award grants to low-income families who need help meeting housing expenses under a $500,000 program begun this year.

The Fairfax County Board of Supervisors approved the program this spring during budget deliberations, and based it on a similar program in Arlington County. Another, more extensive, housing expense relief program is operating in Montgomery County.

"Basically, this is a system to assist 'the working poor,'" said Fairfax Supervisor James M. Scott (D-Providence), who proposed the program to the board. "It is not a great amount of money, but at least it will make the system of raising revenue a little more fair."

He described Fairfax County's taxing system as "a little regressive," saying that families with lower incomes pay a larger proportion of their income to local taxes than do more affluent families.

The program would provide eligible families up to $150 a year to help with housing expenses. The county's Office of Assessment, which operates the program, expects 5,000 families to take advantage of the grants, although many more families are expected to apply.

Homeowners or renters who are between the ages of 55 and 64 or have children under 18 living at home would be eligible for the program, as long as the household's total income does not exceed $10,000 a year, according to the assessments office.

Those already living in subsidized housing or receiving welfare are not eligible under the program, said Paul Smith of the assessments office.

He added that in calculating the $10,000 income limit, the county would exclude $750 for each child under 18 at home. It would also exclude the first $4,000 earned by any other relative, such as aunts or uncles, living in the household.

In addition, the total net worth of the person applying for the relief and his spouse cannot exceed $35,000. This sum does not include the value of their house or land around it, Smith said.

Fairfax County residents must apply no later than Dec. 31 for the program, Smith said, although he is encouraging people to apply as soon as possible after Sept. 1, when application forms become available.

Forms may be obtained at branch assessments offices throughout the county and at the main assessments office and the citizens' assistance counter in the Massey Building, 4100 Chain Bridge Road, Fairfax. For more information on the program, call 691-2437.